1. Field
This application relates to a golf club gauge which measures properties of a golf club head, the gauge using a level in its head squaring and measuring systems.
2. Prior Art
Golf club heads have important properties such as loft angle, lie angle, and face angle which are measured with a tool commonly called a golf club gauge. Golf club heads have a face for hopefully striking a golf ball, a tubular extension called a hosel in which a shaft can be secured, a sole on which the head rests when placed on the ground, a toe which is its end away from the golfer, and a heel which is its end toward the golfer. Most irons and wedges have faces which are flat, while most drivers, fairway woods, and hybrids have faces which are not flat but arcuate. A vertical arc on an arcuate face is called roll, a horizontal arc is called bulge.
Measurements of a head's properties are normally taken with the head in a centered, squared, position, or CSP. For a club head to be in its CSP, several conditions together must be met. With the club's hosel/shaft axis lying in a shaft plane which is perpendicular to a ground plane, the centered condition is met if the head's sole touches the ground plane at a point which is centered on the head's face. The squared condition is met if the head's face line, a line defined by two points on the face equally distant horizontally from the face's center and halfway up the face from the ground plane, is parallel to the shaft plane. When the head is in its CSP, loft angle is the angle the head's face makes with the shaft plane, lie angle is the angle the hosel/shaft axis makes with the ground plane, and face angle is the angle the face line makes with the shaft plane which is zero if the head is in its CSP.
Golf club gauges typically have a frame and a clamping means to secure a club head in positions relative to the frame. They also have a system for squaring the head in the frame and a measuring system to obtain the head's loft, lie, and face angles. A golf club gauge with novel squaring and measuring systems is the object of this Application.
Many current golf club gauges use protractor devices in their squaring and measuring systems, one such gauge being shown in U.S. Pat. No. 2,546,426 to Bryant (1951). Parts 78 and 80 measure the head's lie angle, and 116 and 118 measure its loft angle. Parts 132 and 134 are used to measure the head's face angle and also can be used to square the head in the gauge. These protractor devices must have a relatively large size for sufficient accuracy, resulting in a gauge which is relatively large. Also, there are numerous relatively complex parts, resulting in a gauge with relatively high cost.
A club gauge which uses levels in its measuring system is shown in U.S. Pat. No. 5,105,550 to Shenoha (1992). Two electronic levels are fixed to the gauge's frame, level 105 for measuring a head's loft angle and level 91 for measuring its lie angle, and this requirement for two levels increases the cost of this gauge over one which could function with only one level. FIG. 19 shows a slide assembly 95, a rail 93, and a horizontal plate 97 used to square the head's face, and a spirit level 101 used with level 91 to measure lie angle; these additional parts add further complexity and cost. FIG. 20 shows a protractor device 119 for measuring face angle, adding even more complexity and cost.
It is desirable to have a golf club gauge which uses a level in its head squaring and measuring systems, resulting in a low cost, compact gauge having few parts. It is also desirable that the level be hand-held and electronic with a zeroing function, allowing the gauge to be readily portable and usable in various orientations. Also desirable is an attachment for the level which prevents rocking when the level is placed relative to an arcuate club face.